computing resource paradigms cs3353. computing resource paradigms centralized computing distributed...

Computing Resource Paradigms

CS3353

Computing Resource Paradigms

• Centralized Computing

• Distributed Computing

Early Centralized Computing Paradigm

• Characterized by one central computer.

• Housed in a limited access, climate controlled room.

• A shared resource – users connect through dumb-terminals.

• Limited interactive access.

• Jobs are submitted through batch job-queues.

Centralized Computing

• There remain highly specialized computer systems of this type:

• Supercomputers designed for special resource intensive problem solving.

Cray T3E/512-PE Supercomputer Mainframe

Centralized Computing Advantages

• Ideal for maintaining a high level of security.

• Climate controlled environment is equipment friendly.

• Reduces maintenance costs.

Distributed Paradigm

• Demand driven by departments wanting access to more computing resources beyond the confines of centrally controlled systems.

• Unix becomes a popular operating system for this paradigm.

• HP, Sun, SGI, and others ride this wave during the 1980’s.

DEC Micro-VAX

Client-Server

• The spread of networks and low cost network hardware led to the client-server computing paradigm. This successfully merges the two central and distributed paradigms.

• Computers are interconnected by a network.

• The computers are classified as either clients or servers in the network.

Server

• A powerful computer configured to provide services to other computers within a computing system environment.

• Example Services:– Disk– Printer– Application– E-mail– etc

Server

• The server is typically a powerful computer configured with:

• Fast processors (1 or more)

• Fast and reliable disk storage

• Memory rich

Server

• Central location for the server allows ease of maintenance and high levels of security.

• Simplifying the maintenance of the system helps control costs.

• Small operations (businesses) can put a powerful central computing system in a small room. There it can be relatively secure and easy to maintain.

Server Rack

Behind the Server Rack

The Client

• A client is configured to access specific services within the boundary of the defined computing system environment.

• Client classifications:– Fat client: fully functional workstation– Thin client: a dumb terminal or graphical

display– Hybrid client: between thin and fat.

Client

• Fat clients are fully functional computers with local storage and computing capability.

• Thin clients rely on a server to provide storage and computing resources. Characterized as diskless and without a processor.

• Hybrid clients provide some computing resources independent of a server; storage is provided by a server.

Client

• Thin/Hybrid clients can cost less than fat-clients to purchase and maintain when carefully chosen.

• Work well for:– public access areas– high security environments– When full function workstations are unnecessary.– Reduces maintenance for cost conscious businesses.

$300 client